The present invention relates to power booster cartridges employed by power activated tools for fitting connectors to power cables and, in particular, to a power booster bushing for receiving and positioning a power cell within the power booster cartridge.
U.S. Pat. No. 4,722,189 assigned to Burndy Corporation is directed to an explosively operated tool for connecting a tap or branch cable to a permanently installed main power cable. The power tool uses an explosive charge or power cell which generates sufficient force to drive a wedge into a sleeve connection between the main cable and tap wire.
The power cell described in U.S. Pat. No. 4,722,189 includes a tubular cartridge case, a rim fire power cell held by a supporting collar or power booster bushing slidably fitted in the cartridge case, and a power piston slidably fitted in the cartridge case ahead of the power cell for transmitting explosive force during operation of the power tool. The cartridge case has openings both at its muzzle and breech ends. According to the '189 patent, the power tool is armed when its power ram is inserted into the open muzzle end of the cartridge case as the power tool engages an unfinished connector and the power ram pushes the power piston and power booster bushing with power cell rearwardly so that the power cell is positioned at the open breech end of the cartridge case within range of the firing pin.
Because of the sliding interface between the power booster bushing and the cylindrical interior surface of the cartridge case there is an opportunity for migration of powder gases rearwardly past the interface and outwardly through the breech opening when the power cell is detonated. Such power gas migration tends to diminish the power available for actuating the power tool. Additionally, the powder gases cause erosion of the power tool's breech plug mechanism carrying the firing pin.